If you're worried about having bad breath, I have something good I can tell you about.
この場合、次のような言い方ができますよ。
ーIf you're worried about having bad breath, I have something good I can tell you about.
「口臭が気になるなら、良い物教えてあげるよ」
to be worried about having bad breath で「口臭が気になる」と言えます。
ご参考まで!